Riffle.



J. B. GIFFEN.

RIFFLE.

APPLICATION mio luLv 8.1914.

1,198,342. Pandsept. 12,1916.

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1. a. GIFFEN.

RIFFLE.

APPLlcAloN FILED luLv 9.1914.

Patented Sept. 12, 1916.

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RIFFLE.

APPLlcAnoN FILED JULY 8.1914.

Patented Sept. 12, 1916.

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JAMES B. GIFFEN, OF SAN FRANCISCO, CALIFORNIA.

RIFFLE.

Application led July 8, 1914.

To all whom it may concern:

Be it known that I, JAMES B. G'IFFEN, a citizen of the United States, residing in the city and county of San Francisco and State of California, have invented certain new and useful Improvements in Riliies, of which the following is .a specification.

In stationary riiies, the sand has a tendency .to pack against the rife slats, thus destroying the .efiiciency of the rifile, as all values under such conditions cannot be retained. It .has been proposed to give the rifile a slight vertical movement to overcome this condition, but such movement is objectionable in `that it gives an inertia movement to the values and vprecipitates Vthem over the riflles whereby they are lost.

The object of my invention is to provide the rie slats with an overhanging face which is presented upstream, so as to form a pocket into which the values settle, and then give the riflle a lateral motion which causes the sand and other foreign materials to {ioat off, leaving the values in the pocket; and with fthis and other `objects `in view, my invention consists of the parts and combination of parts as will be more fully hereinafter pointed out.

In the drawings, Figure 1 is a side elevation of an ore concentrator embodying my invention; Fig. 2 isa longitudinal vertical section of the same parts, being in elevation; Fig. 3 is a transverse section on the line AMB, Fig. 1; Fig. 4 is a detail sectional view `taken substantially on the line C, D of Fig. 1. Fig. 5 is an .enlarged detail view ofthe rifie; Fig. 6 is an enlarged detail view of an intermittent gear drive, and i Fig. 7 is a perspective view of a riille board, parts being broken away.

The reference numeral 1 designates a suitable base, on which is mounted the frame 2.

3 is a driving .pulley connected to a suitable source `of power on the shaft of which is a gear wheel 4 meshing with the gear wheel 5. The base 1 is provided with suitable slides 6, in which T-headed standards 7 are adapted to slide, said standards being connected to the frame 2, so that by the mechanism hereinafterv described, the frame 2 may be given a lateral reciprocation, but at the same time is held against any vertical movement by the T-head of the standards 7 fitting under the overhangs of the slides 6.

Specification of Letters Patent.

Patented Sept. 12, 1916.

serial No. 849,769.

n The shaft 8 to which the gear 4 is keyed is provided with two cranks 9, to which vare connected, respectively, pitmen 10, which in turn are connected to yokes 11 secured at their upper ends to the frame 2 in any suitable manner.

11a is a stub shaft connected to the hollow shaft 12 by means of a universal joint l 14 is a. shaft, one end of which is movably mounted within the hollow shaft 12, so that there may be relative lengthwise movement between the shafts 12 and 14, as will be readily understood.

15 is a stub shaft connected to the upper end of shaft 14 by means of the universal joint 16.

17 is a beveled gear having a shaft 18 which passes .transversely through the frame 2 19 is a beveled pinion adapted to intermittently mesh with the beveled gear 17.

20 is a cam mounted on the shaft 15 and .bearing on the central portion ofthe gear 17, so that the pinion 19 is intermittently moved out of and into engagement with the gear 17, the spring 21 tending to normally hold the cam into engagement with the face of the gear 17.

A belt 22 is mounted on the rollers 28 within the frame 2, said belt being provided with ri-iiic slats 24, there being bottom pieces 25 on thebelt between the slats.

2G is a feeding trough for gravel, sand, ore and water, having its discharging end disposed about midway the length of the belt.

27 and 28 are auxiliary water discharging nozzles.

29 is a discharging chute positioned under the delivery end of the endless belt.

As more clearly shown in Fig. 5, the riiie slats 24 have overhanging edges or undercut faces 30, which are the upstream faces of the riiltle slats, the bottom portion 25 being spaced at one edge from, the inclined face of the riffle slat 24 and inclined toward the vertical face of the next adjacent slat. The space between the bottom piece 25 and the inclined face 30 constitutes a. pocket 31, in which quick silver may be placed.

ln Fig. 7, I have shown m invention embodied in a riffle board, in w ich the slats 32 are of the same construction as shown in Fig. 5.

As stated, the overhang or inclined faces CAN 30 of the rime slats are presented upstream. r1`hat is to say, the water flowing over the riflie strikes against the inclined faces, causing an eddy, which deposits the values under the inclined faces so that the values gradually sink into the pockets 31 on the riffle, where they are held securely against loss.

By holding the riliie against vertical motion and at the same time reciprocating it laterally, the metallic particles settle down to and lie on the face of the table, or bottom if the riflle is made in the form. of a tray, and remain practically motionless, but gradually work down the inclined faces of the riflle slat into the trap 31, if a trap is used, and are thus secured against loss by being washed over the rifile.

l/V hen the trap 31 is illed with mercury, it serves as an amalgamator and as a retainer for those particles that will not amalgamate with mercury. The heavy materials, such for instance as platinum when brought into contact with mercury, will, on'

account of the lateral motion of the riile, sink through the mass of mercury and being of greater specific gravity will not again rise to the surface and is thus saved.

Another' feature in connection with the use of mercury is that by reason of its greater specific gravity, it will always lie under sand, and when the riflie or table is in motion no sand will pack in the riffle on account of the sustaining power of the mercury, and the natural tendency of the sand will be to slip off of the surface of the niercury over the riilie slat. In this connection, attention is called to the face that the use of mercury prevents the sand from packing in the riHies. lVhen the sand packs in the ritlles, the efficiency of the rilfle is de` stroycd and no values are retained, where as in my construction when the bed is in motion, the vibrated mass of mercury collects and retains all the values while the sands pass over it without any packing effect.

When my invention is to be used for the recovery of gold only, mercury is not employed and the rile is formed on a traveling belt moving intermittently in a longitudinal direction by means of the gear 17, pinion 19 and cam Q0, while the belt is given a steady, lateral vibration, while the sand, ore, gravel and water are being discharged from the chute 26 onto the belt. The next movement of the rifle longitudinally carries the partially concentrated material back of and away from the feeding point of the chute 26 to a point adjacent to the water nozzle 27, where additional water is applied, thus giving the material a second washing, the belt being laterally reciprocated. The next longitudinal movement of the belt brings the material in position adjacent the water nozzle 28, where the material is again treated and given a further washing. These movements and the subsequent washings may be continued as long as desired, the result being a clean concentrate at the head of the table or point of discharge and prevents the necessity of ceasing operations for the purpose of cleaning the rifllles.

The falling of the ore or sand vertically from the top of the riflle to the bed of the same, and the subsequent washing over the flat or inclined space, causes separation of values from the sands by reason of the lateral motion of the table or rilfle at right angles to the flow of the water carrying the sand, and its separation by specific gravity.

1f my riie inclined upstream (being the opposite to placer and dredger mining practice) should be stationary, all gold would be washed over and lost, but on account of the peculiar effect of the combined movement of the rillle and the water being at right angles to each other, practically all values, no matter how small the particles may be, are, as above explained, washed under the overhang riflle and are thus saved.

1n putting my invention into practice, it is not necessary to erect an especially designed plant, because the rifles may be readily applied to gold dredgers of present construction by making shaking tables of their riiie tables and 'applying riftles with the inclined side upstream; or in hydraulic and sluice box practice by giving one or more sluice boxes a lateral motion and placing the improved riliie bar as above described.

The specific construction of the means illustrated in the drawing for giving the riflle the lateral reciprocations and the intermittent longitudinal movement may be varied at will, without departing from the spirit of my invention.

1 claim 1. A riflle provided with a continuous flat bottom, straight, transverse slats thereon,` each slat having an undercut face presented upstream, a trap pocket at the bottom of said face formed in the inclined bottom between the slats.

2. A rillle having a continuous [iat bottoni member provided with straight transverse slats secured to said bottom, each slat having an undercut front face presented upstream, a filling piece with an inclined upper surface also attached to said bottom and extending from the rear face of one slat part-Way toward the front face of the next so as to form a trap pocket at the bottom of said front face.

3. A gravel washing machine having an inclined, movable riffle with a flush faced, continuous bottom, transverse slats on the bottom each having a perpendicular rear face and a front face forwardly inclined relative to said bottom, the inclined face 19 face forwardly inclined relative to being presented upstream a step being provided on the bottom between each pair o slats, and means to reciprocate the riffle laterally.

Ll. A gravel washing machine having an inclined, movable riflle with a Hush faced continuous bottom provided with a series of steps, transverse slats on the bottom each having a perpendicular rear face and a front said bot- Copies of this patent may be obtained for tom, the inclined face being presented upstream and forming a pocket with the step7 and means to reciprocate the rifile laterally. The foregoing specification signed at Sacramento, California, this 17th day of June, 1914.

JAMES B. GIFFEN. In presence of two Witnesses:

ALMA E. GRADY, VILLIAM E. KLEINsoRGE.

ve cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

